1. Field of the Invention
The present invention relates to a sheet stacking and aligning device for aligning and stacking sheets, a sheet processing apparatus comprising the sheet stacking and aligning device, and an image forming apparatus comprising the sheet processing apparatus.
2. Description of the Related Art
Conventionally, for reducing the occupied area at the time of installing an image forming apparatus and a sheet processing apparatus in the sheet processing apparatus connected with the image forming apparatus such as a printing apparatus, a copying machine, and a printer, there is an image forming apparatus system comprising a sheet processing apparatus 500 between an image forming apparatus main body 200 (printer part) and an original reading device 150 as shown in FIG. 13.
According to the image forming apparatus system, a sheet S with an image formed by the image forming apparatus main body 200 is stacked temporarily on a processing tray 540 in the sheet processing apparatus 500 so as to execute the sheet process such as the aligning and binding process for the sheets S, or the like thereat. Thereafter, they are discharged to a stack tray 581 having an inclined stacking surface as shown in FIG. 13 by a bundle discharging means 580. The discharged sheets S are moved on the inclined stacking surface of the stack tray by their self weight so as to have the sheet rear end aligned by the rear end aligning wall. The number of the stacked sheets depends on the width of the vertically movable stroke of the stack tray 581.
Moreover, according to another sheet processing apparatus 500 connected with the image forming apparatus, for changing the binding position in the binding process to be executed by the sheet processing apparatus according to the paper size of the sheet S discharged from the image forming apparatus, the image orientation, the mode set by the user, or the like, a stapler for executing the binding process can be moved.
In contrast, in the case the sheet is choked in the feeding path 510 of the sheet processing apparatus 500, a left door 210 of the image forming apparatus main body 200 is opened in the arrow X direction of FIG. 13 and the upper feeding guide 501 of the sheet processing apparatus 500 is opened in the arrow Y direction for eliminating the choked sheet.
However, in the case the sheet is choked in the feeding path 510 of the sheet processing apparatus 500, since the choked sheet is eliminated by opening the upper feeding guide 501 of the sheet processing apparatus 500 in the arrow B direction, a problem is involved in that an space for opening the upper feeding guide 501 is required in the upper part of the upper feeding guide 501.
Moreover, since the number of sheets to be stacked on the sheet processing apparatus 500 depends on the vertical movable stroke of the stack tray 581, for enlarging the number of sheets to be stacked, the sheet processing apparatus should be shifted upward for enlarging the vertical movable stroke of the stack tray 581.
Therefore, in order to provide the space for eliminating the sheets choked in the feeding path 510 and enlarging the number of sheets to be stacked-on the stack tray 581, a problem is involved in that the entire apparatus becomes bulky and the cost is increased.